Operating leverage problem

CFA Level I
#1

Which of the following is most likely to increase a business’s operating leverage?
A. Reducing prices
B. Borrowing rather than issuing equity
C. Using casual labor rather than a salaried work force

I have not clue about this problem
Can someone tell me?
Thanks

#2

What, specifically, causes operating leverage?

#3

fixed cost and total cost?

#4

Just fixed (operating) costs.

So . . . which answer choice affects fixed operating costs?

#5

the last one?

#6

Say it like you mean it.